LOCATION PAPAI HI

Established Series
Rev. RCH/HHS/PGN/AMS/KP
06/2012

PAPAI SERIES

The Papai series consists of deep and very deep, well drained soils consisting of organic material over fragmental `a`a lava substrata at a shallow depth. Papai soils formed in organic material over `a`a lava and are on low elevation, windward slopes of Mauna Loa and Kilauea shield volcanoes. Slopes range from 2 to 10 percent. Mean annual rainfall is about 3900 millimeters (154 inches) and mean annual temperature is about 22 degrees C (72 degrees F).

TAXONOMIC CLASS: Euic, isohyperthermic Typic Udifolists

TYPICAL PEDON: Papai extremely cobbly highly decomposed plant material on a northeast-facing, 2 percent slope in lowland forest at an elevation of 111 meters (363 feet). (Colors are for moist soils unless otherwise notedWhen described on June 16, 2005, the soil was moist from 0 to 26 centimeters (0 to 10 inches).)

2C1/Oa--0 to 26 centimeters (0 to 10 inches); black (10YR 2/1) extremely cobbly highly decomposed plant material, very dark brown (10YR 2/2) dry; moderate very fine granular structure; very friable, non sticky, non plastic; common fine and few coarse roots throughout; common very fine dendritic pores throughout; non smeary; 20 percent subangular `a`a lava stones, 30 percent subangular `a`a lava cobbles and 15 percent subangular `a`a lava gravel; strongly acid (pH 5.4); the 2C part of the horizon consists of unconsolidated `a`a lava fragments of variable size; abrupt wavy boundary. (8 to 30 centimeters {3 to 12 inches} thick)

2C2--26 to 135 centimeters (10 to 53 inches); fragmental `a`a lava; 5 percent soil material from above horizon in voids and cracks; 30 percent subangular `a`a lava stones, 35 percent subangular `a`a lava cobbles and 30 percent subangular `a`a lava gravel; the 2C part of the horizon consists of unconsolidated `a`a lava fragments of variable size; abrupt wavy boundary. (100 to 150 centimeters {40 to 60 inches} thick)

2R--135 centimeters (53 inches); Hard, massive, `a`a lava blue rock.

TYPE LOCATION: Island of Hawaii. From the city of Hilo proceed south on Highway 11 to West Mamaki Street. Turn right, west, and proceed 0.25 miles to Kealakai Street and turn left, south. Proceed 0.85 miles to the nursery on the southwest side of road. Follow driveway to the edge of the forest, park and proceed approximately 200 feet southwest to the type location at Hilo Quadrangle; 19 degrees, 39 minutes, 01.9 seconds North latitude and 155 degrees 03 minutes 39.6 seconds West longitude (Old Hawaiian Datum, +/- 12 ft; measured by Garmin GPS).

RANGE IN CHARACTERISTICS:
Soil moisture: The soil is typically moist throughout the profile. Precipitation exceeds evapotranspiration in all months of normal years (perudic soil moisture regime).
Soil temperature: 22 degrees C (72 degrees F) or higher.
Reaction: Strongly acid (5.1 to 5.5).

Oe or Oi horizon (when present)
Hue: 7.5YR or 10YR.
Value: 2 or 3 moist.
Chroma: 1 or 2 moist.
Texture: Moderately decomposed plant material or slightly decomposed plant material.
Structure: Granular or structureless.

Oa horizon
Hue: 7.5YR or 10YR.
Value: 2 to 2.5 moist.
Chroma: 1 to 2.
Structure: Moderate to strong granular.
Rock fragments: 60 to 85 percent by volume of the pedon and range in size from gravel to cobble size `a`a lava rocks.

C2
Rock fragments: 90 to 99 percent by volume of the pedon and range in size from gravel to cobble size `a`a lava rocks.

COMPETING SERIES: These are the Malama and Tafuna series. Malama soils are udic and have a mean annual rainfall of 1905 millimeters (75 inches). Tafuna soils are slightly acid and have a mean annual temperature of 27 degrees C (80 degrees F).

GEOGRAPHIC SETTING: The Papai soils are at elevations ranging from 0 to 366 meters (0 to 1,200 feet) on the low windward slopes of Mauna Loa and Kilauea shield volcanoes. These soils form in a thin mantle of organic material overlying `a`a lava. These soils are in constructional landscapes consisting of undulating `a`a lava flows that are 400 to 1500 years old. Slope gradients range from 2 to 10 percent. Mean annual rainfall is 3000 to 5000 millimeters (118 to 197 inches) with most of the rainfall occurring from October through April. The mean annual pan evaporation ranges from 762 to 1016 millimeters (30 to 40 inches). The mean annual air temperature ranges from 21 to 23 degrees C (70 to 73 degrees F). The mean annual soil temperature is 22 degrees C or higher (71 degrees F).

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Keaukaha, Olaa, and Panaewa series. Keaukaha soils have lithic contact within 25 centimeters of the surface. Olaa soils form in volcanic ash over `a`a lava and are moderately deep. Panaewa soils are skeletal and have lithic contact within 40 centimeters of the surface.

DRAINAGE AND PERMEABILITY: Well drained. Negligible to low runoff. Permeability is very rapid in the soil and fragmental material and very slow in the underlying bedrock.

USE AND VEGETATION: These soils are forested or used for pasture, macadamia nut trees (Macadamia spp.), or papaya (Carica papaya). Natural vegetation is ohia lehua (Metrosideros polymorpha), treefern (Cibotium spp.), and uluhe (Dicranopteris linearis).

DISTRIBUTION AND EXTENT: Island of Hawaii. This series is moderately extensive with approximately 17,000 acres. MLRA 162 - Humid and Very Humid Organic Soils on Lava Flows.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.

SERIES ESTABLISHED: Hawaii County, Hawaii, 1971.

REMARKS:
Last revised by state on 5/09 PGN & AMS.

All textures are "apparent field textures". pH measured using an Oakton microprocessor based pH meter.

Diagnostic horizons and features (9th edition Keys to Soil Taxonomy) recognized in this pedon are:
Sapric soil materials - from a depth of 0 to 26 centimeters (0 to 10 inches) (Oa horizon).
Isohyperthermic soil temperature regime.
Perudic soil moisture regime.

National Cooperative Soil Survey
U.S.A.